Secondary battery

ABSTRACT

A secondary battery includes an electrode, a positive electrode current collector, a negative electrode current collector, a positive electrode terminal, a negative electrode terminal, and an insulating plate. The positive electrode terminal and the negative electrode terminal each have a main side surface and a sub side surface having an area smaller than that of the main side surface. The positive electrode terminal and the negative electrode terminal are arranged so that the main side surface of the positive electrode terminal and the main side surface of the negative electrode terminal face each other. The insulating plate is arranged between the main side surface of the positive electrode terminal and the main side surface of the negative electrode terminal.

This nonprovisional application is based on Japanese Patent ApplicationNo. 2020-152873 filed on Sep. 11, 2020 with the Japan Patent Office, theentire contents of which are hereby incorporated by reference.

BACKGROUND Field

The present disclosure relates to a secondary battery.

Description of the Background Art

For example, Japanese Patent Laying-Open No. 2016-25014 discloses a filmexterior battery having a flat laminate film exterior body. This filmexterior battery has a pair of tabs protruding from the laminate filmexterior body. One of the pair of tabs is a positive electrode tab, andthe other of the pair of tabs is a negative electrode tab. Each tabextends parallel to a flat surface of the laminate film exterior body.The pair of tabs are provided at one end of the laminate film exteriorbody. The pair of tabs are arranged to be aligned in a directionorthogonal to a thickness direction of each tab.

SUMMARY

In the secondary battery described in Japanese Patent Laying-Open No.2016-25014, since the positive electrode tab and the negative electrodetab are arranged to be aligned in the direction orthogonal to thethickness direction of each tab, it is necessary to increase thethickness of each tab in order to increase the cross sectional area ofeach tab to suppress heat generation at each tab when applying acurrent, while securing insulation between the tabs. That is, in thesecondary battery described in Japanese Patent Laying-Open No.2016-25014, the degree of freedom of the design of each tab is smallwhen increasing the cross sectional area of each tab while securinginsulation between the tabs.

An object of the present disclosure is to provide a battery module thatcan secure insulation between terminals and can also increase the degreeof freedom of the design of the terminals.

A secondary battery according to one aspect of the present disclosureincludes an electrode; a positive electrode current collector providedat one end of the electrode in one direction; a negative electrodecurrent collector provided at the one end of the electrode in the onedirection; a positive electrode terminal connected to the positiveelectrode current collector and formed in a flat plate shape; a negativeelectrode terminal connected to the negative electrode current collectorand formed in a flat plate shape; and an insulating plate that insulatesbetween the positive electrode terminal and the negative electrodeterminal, the positive electrode terminal and the negative electrodeterminal each having a main side surface and a sub side surface havingan area smaller than that of the main side surface, the positiveelectrode terminal and the negative electrode terminal being arranged sothat the main side surface of the positive electrode terminal and themain side surface of the negative electrode terminal face each other,the insulating plate being arranged between the main side surface of thepositive electrode terminal and the main side surface of the negativeelectrode terminal.

The foregoing and other objects, features, aspects and advantages of thepresent disclosure will become more apparent from the following detaileddescription of the present disclosure when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view schematically showing a configuration of asecondary battery in one embodiment of the present disclosure.

FIG. 2 is a front view showing a state where a laminate exterior body isremoved from the secondary battery shown in FIG. 1 .

FIG. 3 is a left side view of the secondary battery.

FIG. 4 is a cross sectional view taken along a line IV-IV in FIGS. 1 and3 .

FIG. 5 is an exploded view of the secondary battery.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present disclosure will be described with referenceto the drawings. It should be noted that, in the drawings referred tobelow, identical or corresponding members will be designated by the samereference numerals.

FIG. 1 is a front view schematically showing a configuration of asecondary battery in one embodiment of the present disclosure. Thissecondary battery 1 is mounted, for example, on a vehicle. Examples ofsecondary battery 1 include a lithium ion battery.

As shown in FIG. 1 , secondary battery 1 includes an electrode body unit10, a terminal unit 20, and a laminate exterior body 30.

Electrode body unit 10 has a pair of electrodes 12A and 12B, a separator14, a positive electrode current collector 16A, a negative electrodecurrent collector 16B, and fixing portions 18.

Each of electrodes 12A and 12B is formed in the shape of a thin film ora thin flat plate. Each of electrodes 12A and 12B is formed in the shapeof a rectangle that is long in one direction. One of the pair ofelectrodes is positive electrode 12A, and the other of the pair ofelectrodes is negative electrode 12B. Electrodes 12A and 12B arearranged to face each other in a thickness direction of the electrodes.

As shown in FIG. 4 , separator 14 is provided between the pair ofelectrodes 12A and 12B.

Positive electrode current collector 16A is electrically connected topositive electrode 12A. Specifically, positive electrode currentcollector 16A is provided at one end of positive electrode 12A in theone direction (see FIGS. 1 and 2 ). The length of positive electrodecurrent collector 16A in an orthogonal direction (see FIGS. 1 and 2 )orthogonal to both the one direction and the thickness direction ofelectrodes 12A and 12B is set to be less than half of the length of eachof electrodes 12A and 12B in the orthogonal direction. Positiveelectrode current collector 16A is made of metallic foil.

Negative electrode current collector 16B is electrically connected tonegative electrode 12B. Specifically, negative electrode currentcollector 16B is provided at one end of negative electrode 12B in theone direction. The length of negative electrode current collector 16B inthe orthogonal direction is set to be less than half of the length ofeach of electrodes 12A and 12B in the orthogonal direction. Negativeelectrode current collector 16B is made of metallic foil.

As shown in FIG. 1 , positive electrode current collector 16A andnegative electrode current collector 16B are arranged at positionsseparated from each other in the orthogonal direction. As shown in FIG.4 , positive electrode current collector 16A and negative electrodecurrent collector 16B are arranged at positions separated from eachother in the thickness direction of electrodes 12A and 12B (directionorthogonal to both the one direction and the orthogonal direction).

Fixing portions 18 fix electrodes 12A and 12B. Fixing portions 18 fixone edge and the other edge of each of electrodes 12A and 12B in theorthogonal direction. Fixing portions 18 have a shape extending alongthe one direction. Fixing portions 18 are made of resin.

Each fixing portion 18 has a positioning portion 18 a for positioningterminal unit 20. Positioning portion 18 a is formed at an end of fixingportion 18 on one side (side where current collectors 16A and 16B areprovided) in the one direction. In the present embodiment, positioningportion 18 a is composed of a recess.

Terminal unit 20 is a unit attached to electrode body unit 10. Terminalunit 20 has a positive electrode terminal 22A, a negative electrodeterminal 22B, a holder 24, and an insulating plate 26.

Positive electrode terminal 22A and negative electrode terminal 22B areeach formed in a flat plate shape. Positive electrode terminal 22A iselectrically connected to positive electrode current collector 16A.Negative electrode terminal 22B is electrically connected to negativeelectrode current collector 16B.

Positive electrode terminal 22A and negative electrode terminal 22B eachhave a main side surface S1 and a sub side surface S2. Sub side surfaceS2 has an area smaller than that of main side surface S1. Positiveelectrode terminal 22A and negative electrode terminal 22B are arrangedso that main side surface S1 of positive electrode terminal 22A and mainside surface S1 of negative electrode terminal 22B face each other.

As shown in FIG. 2 , the dimension of each of terminals 22A and 22B inthe orthogonal direction is larger than the dimension of each of currentcollectors 16A and 16B in the orthogonal direction. In the presentembodiment, the dimension of each of terminals 22A and 22B in theorthogonal direction is set to be substantially the same as a distancebetween an outer end of positive electrode current collector 16A and anouter end of negative electrode current collector 16B in the orthogonaldirection.

Holder 24 holds terminals 22A and 22B. Specifically, holder 24 holdspositive electrode terminal 22A and negative electrode terminal 22B sothat main side surface S1 of positive electrode terminal 22A and mainside surface S1 of negative electrode terminal 22B face each other.Holder 24 holds terminals 22A and 22B in a state where terminals 22A and22B are inserted into holder 24 in the one direction. Holder 24 is madeof resin. In the present embodiment, positive electrode terminal 22A andnegative electrode terminal 22B are insert-molded into holder 24.

Holder 24 has an inner surface 24S1 facing electrodes 12A and 12B, andan outer surface 24S2 opposite to inner surface 24S1. Inner surface 24S1is flatly formed. Outer surface 24S2 is flatly formed. For example,outer surface 24S2 can be used to position secondary battery 1.

Holder 24 has attached portions 24 a attached to fixing portions 18.Attached portions 24 a are provided on inner surface 24S1. In thepresent embodiment, each attached portion 24 a is composed of aprojection that fits in positioning portion 18 a. It should be notedthat positioning portion 18 a may be composed of a projection andattached portion 24 a may be composed of a recess.

Insulating plate 26 insulates between positive electrode terminal 22Aand negative electrode terminal 22B. Insulating plate 26 is arrangedbetween main side surface S1 of positive electrode terminal 22A and mainside surface S1 of negative electrode terminal 22B. Insulating plate 26is connected to holder 24. Insulating plate 26 is made of resin.Preferably, insulating plate 26 is integrally molded with holder 24.

As shown in FIGS. 1 and 2 , insulating plate 26 has a protruding portion26 a. Protruding portion 26 a has a shape protruding from positiveelectrode terminal 22A and negative electrode terminal 22B wheninsulating plate 26 is viewed in a facing direction in which positiveelectrode terminal 22A and negative electrode terminal 22B face eachother. That is, the outer shape of insulating plate 26 is larger thanthe outer shape of each of terminals 22A and 22B.

Laminate exterior body 30 is provided around fixing portions 18 andholder 24. As shown in FIG. 5 , laminate exterior body 30 is formed bywinding a resin film around fixing portions 18 and holder 24 afterterminal unit 20 is connected to electrode body unit 10.

As described above, in this secondary battery 1, since insulating plate26 is arranged between positive electrode terminal 22A and negativeelectrode terminal 22B, insulation between terminals 22A and 22B issecured. Further, since positive electrode terminal 22A and negativeelectrode terminal 22B are arranged so that main side surfaces S1thereof face each other, the cross sectional area of each of terminals22A and 22B can be adjusted by adjusting the area of main side surfaceS1. Accordingly, this secondary battery 1 can secure insulation betweenterminals 22A and 22B and can also increase the degree of freedom of thedesign of terminals 22A and 22B.

A person skilled in the art would understand that the exemplaryembodiment described above is a specific example of the followingaspects.

A secondary battery in the embodiment described above includes: anelectrode; a positive electrode current collector provided at one end ofthe electrode in one direction; a negative electrode current collectorprovided at the one end of the electrode in the one direction; apositive electrode terminal connected to the positive electrode currentcollector and formed in a flat plate shape; a negative electrodeterminal connected to the negative electrode current collector andformed in a flat plate shape; and an insulating plate that insulatesbetween the positive electrode terminal and the negative electrodeterminal, the positive electrode terminal and the negative electrodeterminal each having a main side surface and a sub side surface havingan area smaller than that of the main side surface, the positiveelectrode terminal and the negative electrode terminal being arranged sothat the main side surface of the positive electrode terminal and themain side surface of the negative electrode terminal face each other,the insulating plate being arranged between the main side surface of thepositive electrode terminal and the main side surface of the negativeelectrode terminal.

In this secondary battery, since the insulating plate is arrangedbetween the positive electrode terminal and the negative electrodeterminal, insulation between the terminals is secured. Further, sincethe positive electrode terminal and the negative electrode terminal arearranged so that the main side surfaces thereof face each other, thecross sectional area of each of the terminals can be adjusted byadjusting the area of the main side surface. Accordingly, this secondarybattery can secure insulation between the terminals and can alsoincrease the degree of freedom of the design of the terminals.

Further, since each terminal can be thinned, each terminal can have animproved weldability. Furthermore, since each terminal has a reducedflexural rigidity due to thinning, absorption of cell pitch displacementdue to expansion and contraction of the electrode or the like can beimproved.

In addition, preferably, the insulating plate has a protruding portionprotruding from the positive electrode terminal and the negativeelectrode terminal when the insulating plate is viewed in a facingdirection in which the positive electrode terminal and the negativeelectrode terminal face each other.

Such a configuration suppresses the positive electrode terminal and thenegative electrode terminal from coming into contact with each other dueto deformation of the terminals or the like.

In addition, preferably, the secondary battery further includes: afixing portion that fixes the electrode; and a holder that holds thepositive electrode terminal and the negative electrode terminal so thatthe main side surface of the positive electrode terminal and the mainside surface of the negative electrode terminal face each other, whereinthe insulating plate is connected to the holder, and the holder is fixedto the fixing portion.

In addition, preferably, the secondary battery further includes alaminate exterior body provided around the fixing portion and theholder.

This manner suppresses the laminate exterior body from peeling off fromeach terminal when an external force acts on each terminal due toexpansion and contraction of the electrode or the like, as compared witha case where the laminate exterior body is welded to each terminal.

Although the embodiment of the present disclosure has been described, itshould be understood that the embodiment disclosed herein isillustrative and non-restrictive in every respect. The scope of thepresent disclosure is defined by the scope of the claims, and isintended to include any modifications within the scope and meaningequivalent to the scope of the claims.

What is claimed is:
 1. A secondary battery comprising: a positiveelectrode; a negative electrode; a positive electrode current collectorprovided at one end of the positive electrode in one direction; anegative electrode current collector provided at one end of the negativeelectrode in the one direction; a positive electrode terminal connectedto the positive electrode current collector and formed in a flat plateshape; a negative electrode terminal connected to the negative electrodecurrent collector and formed in a flat plate shape; a laminate exteriorbody provided around the positive electrode, the negative electrode, thepositive electrode current collector, and the negative electrode currentcollector; an insulating plate that insulates between the positiveelectrode terminal and the negative electrode terminal, the positiveelectrode terminal and the negative electrode terminal each having aprotruding portion protruding from the laminate exterior body in the onedirection, each protruding portion having a main side surface and a subside surface having an area smaller than that of the main side surface,the positive electrode terminal and the negative electrode terminalbeing arranged so that the main side surface of the protruding portionof the positive electrode terminal and the main side surface of theprotruding portion of the negative electrode terminal face each other,the insulating plate being arranged between the main side surface of theprotruding portion of the positive electrode terminal and the main sidesurface of the protruding portion of the negative electrode terminal; afixing portion that fixes the positive and negative electrodes; and aholder that holds the positive electrode terminal and the negativeelectrode terminal so that the main side surface of the protrudingportion of the positive electrode terminal and the main side surface ofthe protruding portion of the negative electrode terminal face eachother, wherein: the insulating plate is connected to the holder, and theholder is fixed to the fixing portion.
 2. The secondary batteryaccording to claim 1, wherein the insulating plate has a protrudingportion protruding from the positive electrode terminal and the negativeelectrode terminal when the insulating plate is viewed in a facingdirection in which the positive electrode terminal and the negativeelectrode terminal face each other.
 3. The secondary battery accordingto claim 1, wherein the laminate exterior body is provided around thefixing portion and the holder.